Event-callback shorthand

[si4-mtg]

Describe the problem

When the name of event handler and event itself is same:
<Component on:changeNum={changeNum} />

Describe the proposed solution

Is nice to have a shorthand:
<Component on: {changeNum} />
<domElem on: {click} />

Alternatives considered

ver: 3.44.3

Importance

nice to have

[msandrini]

Two notes:

• Remember that <Component on:changeNum /> will forward the event (just to be clearer to whoever sees this issue);
• Usually the way of dealing with event callbacks is, for example, for a click event, to have a function called handleClick or onClick. That's one possible reason why such a shortcut wasn't implemented, I would guess.

[Mlocik97]

I'm against that syntax, as it could lead to missunderstanding what is prop and what is handler... but I'm for idea its self,... just with different syntax.

[mdynnl]

The only directive that does not have shorthand is specifically this on:event which is already used as event forwarding. Others simply shorthand even the new style:prop. If a new concise event forwarding syntax were to be introduced maybe v4 which would be breaking, this could be supported to shorthand syntax which is a reasonable change for consistency.

Disclaimer: I'm not currently involved with maintaining svelte and above are all my opinions.

[Rich-Harris]

Closing, as events have been overhauled in Svelte 5